Blow molding is typically used to manufacture products that have hollow interiors or container products that have storage areas. Such container products include a variety of containers that are used for storage and transport of materials. In a blow molding process, parison is injected or placed in a mold that has an interior cavity with a shape that corresponds to the shape of the blow molded article. The parison is then expanded to the shape of the cavity by having air blown therein.
In certain blow molding processes, the parison fills a narrow area of the mold to create a compression area. A compression area of a blow molded article is typically not hollow and may provide a structural support function for the blow molded article. To create a hole in the compression area that has an axis parallel to the open and close direction of the mold, the mold typically includes a pin that is disposed in the compression area, forming part of the mold during the blow molding process. When the mold is opened, the pin is extracted from the compression area to expose a hole in the space occupied by the pin during the blow molding process.
To create a hole in the compression area of the blow molded article that has an axis oriented transverse to the open and close direction of the mold, the blow molded article is first manufactured by blow molding without forming the hole. The hole is then either drilled or punched out of the compression area after the blow molded article is taken out of the mold.